Assessing nature of clogging in zeolite based stormwater filters

Clogging of filter media is recognised as main limiting factor of the stormwater filtration and infiltration systems that are now widely used in the management of polluted urban runoff. An understanding of pollutant migration and location of clogged material could have important connotations for design, operation and especially maintenance of these filtration-based systems. However, conflicting information is available on the extent of clogging that occurs within the filter bed. Effect of filter bed design; inflow sediment characteristics and hydraulic/hydrology characteristics on the nature of clogging/ location of clogged material has been studied. Profiling of clogged columns with different particle sizes suggests that a combination of cake and depth filtration contribute to the clogging of these systems. While surface clogging was still dominant in configurations with different depths, the deeper columns had the lowest proportion of sediment retained in the surface layer. The concentration of sediment and the size of sediment in stormwater were found to impact the location of clogged material. However, presence of other pollutants in stormwater and the hydraulic/hydrology characteristics of catchment had limited effect on the nature of clogging